Parkland Memorial Hospital officials said Friday afternoon that three of the 15 people being treated after Thursday's deadly charter bus crash have been discharged and that four others are expected to leave the intensive care unit.

Two people were killed and 44 people were injured when a charter bus on the way to an Oklahoma casino crashed into a highway retaining wall and rolled onto its side along the President George Bush Turnpike on Thursday morning.

Six of the 12 people that remain in Parkland's care remained in intensive care Friday.

Dr. Alexander Eastman, Parkland interim medical director, said he expected only two patients would still be in the ICU by the end of the day.

Parkland implemented a Code Yellow alert after the crash, and 500 staff members responded. Hospital officials said 500 staff members responded to the alert, saying staff performed beyond their already high expectations.

Due to the additional staff on hand, administrators said the 120 or so patients in the emergency room at the time of the crash did not suffer a lack of care because of the increased demand from the crash victims.

Hospital officials said most of the injuries sustained by the crash victims were consistent with motor vehicle crashes in which people were not wearing seat belts, including broken bones, lacerations and soft-tissue injuries.

In the treatment of those patients, hospital officials said 33 CT scans were performed, 56 X-rays were performed and three MRIs were performed.